The present invention relates to a process for preparing gelled overbased materials and to coatings and other substances containing such gelled overbased materials.
Overbased additives have been known for a long time. They have been used extensively as industrial lubricants in engines, gears and other industrial applications. Specifically they have been used as detergents, extreme pressure and antiwear agents, anticorrosion and antirust additives, and as rheology control agents in coatings. They are metal salts of acidic organic compounds. Overbased materials are single phase, homogenous, and generally apparently Newtonian systems characterized by a metal content in excess of that which would be present according to the stoichiometry of the metal and the particular acidic organic compound reacted with the metal. They can be converted from their original Newtonian form to a gelled form by a variety of treatments.
U.S. Pat. No. 5,501,807, Benda et al., Mar. 26, 1996 discloses a process for producing basic calcium carboxylic acid salts which includes carbonating a mixture of a C.sub.7 to C.sub.15 carboxylic acids which are preferably branched chain oxo-acids and excess calcium at from 15.degree. to 60.degree. C., in the presence of a volatile solvent.
U.S. Pat. No. 5,300,242 Nichols et al., Apr. 5, 1994 discloses a metal overbased composition prepared by reacting
(A) at least one epoxidized natural oil having an oxirane oxygen content of at least 3%, wherein said natural oil is a vegetable oil comprising a triglyceride of the formula ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3 are unsaturated aliphatic hydrocarbyl groups containing from about 8 to 22 carbon atoms with
(B) a metal base oxide (MO), hydroxide (MOH) or alkoxide (R.sup.4 OM) wherein the metal comprises an alkali or alkaline earth and R.sup.4 is a hydrocarbyl group containing from about 1 to about 24 carbon atoms, in an equivalent ratio of (A):(B) from 0.90-10:1 to from a saponified intermediate, adding 2-11 equivalents of (B) per equivalent of said saponified intermediate and reacting excess (B) with
(C) carbon dioxide.
U.S. Pat. No. 5,508,331, Nichols et al., Apr. 16, 1996, discloses a heat stabilized PVC composition comprising PVC and a metal overbased composition, wherein the metal overbased composition is prepared by reacting (A) at least one vegetable oil comprising a triglyceride of the formula ##STR2## wherein R.sup.1, R.sup.2 and R.sup.3 are independently saturated or unsaturated aliphatic hydrocarbyl groups containing from about 8 to 24 carbon atoms with (B) a metal base oxide (MO), hydroxide (MOH) or alkoxide (R.sup.4 OM) wherein the metal comprises an alkali or alkaline earth and R.sup.4 is a hydrocarbyl group containing from about 1 to about 24 carbon atoms, and wherein the equivalent ratio of (A):(B) is from 1.33-10:1 to from a saponified intermediate, adding 2-11 equivalents of (B) per equivalent of formed saponified intermediate and reacting excess (B) with
(C) an acidic gas comprising carbon dioxide, sulfur dioxide or sulfur trioxide.
U.S. Pat. No. 3,816,310, Hunt, Jun. 11, 1974, discloses a method of preparing highly basic, metal containing grease and rust inhibiting compositions which is carried out by (1) forming an admixture of an oil-soluble dispersing agent, an alcohol, water, and an alkaline earth metal oxide, hydroxide, or lower alkoxide; (2) carbonating the admixture to form the alkaline earth metal carbonate; and (3) heating the mixture in a controlled manner to effect a modification reaction in which the grease or rust inhibiting composition is formed as evidenced by a rapid change in the viscosity of the mixture. In an alternative embodiment of the method the water is added after the carbonation step and prior to the heating step.